I didn't even know the Chinese SVD (Dragunovs) were also known as the Type 79 (or Type 79/85, I wonder if that 79/85 is just a US collectors' term). Upon thinking about it further, they're probably all starting from 1979 as 1st year of production, with the first digit being the year code for those in the first two table pictures. It sure would help to have some more feature data etc. in the tables.
I'm guessing all the Type 79 examples in the "green table" below chambered in 7.62x51mm (aka NDM 86) for the American market, were made later, i.e., 10th year, 1988. That seems to sync with the export or American collector's term of NDM 86.
I couldn't get this table to load from the original post so I grabbed it from GB. Helps to be able to see the headings